git.oblomov.eu Git - git/blob - transport-helper.c

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "remote.h"
   9 #include "string-list.h"
  10 #include "thread-utils.h"
  11 #include "sigchain.h"
  12 #include "argv-array.h"
  13 #include "refs.h"
  14 #include "refspec.h"
  15 #include "transport-internal.h"
  16 #include "protocol.h"
  17
  18 static int debug;
  19
  20 struct helper_data {
  21         const char *name;
  22         struct child_process *helper;
  23         FILE *out;
  24         unsigned fetch : 1,
  25                 import : 1,
  26                 bidi_import : 1,
  27                 export : 1,
  28                 option : 1,
  29                 push : 1,
  30                 connect : 1,
  31                 stateless_connect : 1,
  32                 signed_tags : 1,
  33                 check_connectivity : 1,
  34                 no_disconnect_req : 1,
  35                 no_private_update : 1;
  36
  37         /*
  38          * As an optimization, the transport code may invoke fetch before
  39          * get_refs_list. If this happens, and if the transport helper doesn't
  40          * support connect or stateless_connect, we need to invoke
  41          * get_refs_list ourselves if we haven't already done so. Keep track of
  42          * whether we have invoked get_refs_list.
  43          */
  44         unsigned get_refs_list_called : 1;
  45
  46         char *export_marks;
  47         char *import_marks;
  48         /* These go from remote name (as in "list") to private name */
  49         struct refspec rs;
  50         /* Transport options for fetch-pack/send-pack (should one of
  51          * those be invoked).
  52          */
  53         struct git_transport_options transport_options;
  54 };
  55
  56 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  57 {
  58         if (debug)
  59                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  60         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
  61                 die_errno(_("full write to remote helper failed"));
  62 }
  63
  64 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  65 {
  66         strbuf_reset(buffer);
  67         if (debug)
  68                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  69         if (strbuf_getline(buffer, helper) == EOF) {
  70                 if (debug)
  71                         fprintf(stderr, "Debug: Remote helper quit.\n");
  72                 return 1;
  73         }
  74
  75         if (debug)
  76                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  77         return 0;
  78 }
  79
  80 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  81 {
  82         return recvline_fh(helper->out, buffer);
  83 }
  84
  85 static void write_constant(int fd, const char *str)
  86 {
  87         if (debug)
  88                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  89         if (write_in_full(fd, str, strlen(str)) < 0)
  90                 die_errno(_("full write to remote helper failed"));
  91 }
  92
  93 static const char *remove_ext_force(const char *url)
  94 {
  95         if (url) {
  96                 const char *colon = strchr(url, ':');
  97                 if (colon && colon[1] == ':')
  98                         return colon + 2;
  99         }
 100         return url;
 101 }
 102
 103 static void do_take_over(struct transport *transport)
 104 {
 105         struct helper_data *data;
 106         data = (struct helper_data *)transport->data;
 107         transport_take_over(transport, data->helper);
 108         fclose(data->out);
 109         free(data);
 110 }
 111
 112 static void standard_options(struct transport *t);
 113
 114 static struct child_process *get_helper(struct transport *transport)
 115 {
 116         struct helper_data *data = transport->data;
 117         struct strbuf buf = STRBUF_INIT;
 118         struct child_process *helper;
 119         int duped;
 120         int code;
 121
 122         if (data->helper)
 123                 return data->helper;
 124
 125         helper = xmalloc(sizeof(*helper));
 126         child_process_init(helper);
 127         helper->in = -1;
 128         helper->out = -1;
 129         helper->err = 0;
 130         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 131         argv_array_push(&helper->args, transport->remote->name);
 132         argv_array_push(&helper->args, remove_ext_force(transport->url));
 133         helper->git_cmd = 0;
 134         helper->silent_exec_failure = 1;
 135
 136         if (have_git_dir())
 137                 argv_array_pushf(&helper->env_array, "%s=%s",
 138                                  GIT_DIR_ENVIRONMENT, get_git_dir());
 139
 140         helper->trace2_child_class = helper->args.argv[0]; /* "remote-<name>" */
 141
 142         code = start_command(helper);
 143         if (code < 0 && errno == ENOENT)
 144                 die(_("unable to find remote helper for '%s'"), data->name);
 145         else if (code != 0)
 146                 exit(code);
 147
 148         data->helper = helper;
 149         data->no_disconnect_req = 0;
 150         refspec_init(&data->rs, REFSPEC_FETCH);
 151
 152         /*
 153          * Open the output as FILE* so strbuf_getline_*() family of
 154          * functions can be used.
 155          * Do this with duped fd because fclose() will close the fd,
 156          * and stuff like taking over will require the fd to remain.
 157          */
 158         duped = dup(helper->out);
 159         if (duped < 0)
 160                 die_errno(_("can't dup helper output fd"));
 161         data->out = xfdopen(duped, "r");
 162
 163         write_constant(helper->in, "capabilities\n");
 164
 165         while (1) {
 166                 const char *capname, *arg;
 167                 int mandatory = 0;
 168                 if (recvline(data, &buf))
 169                         exit(128);
 170
 171                 if (!*buf.buf)
 172                         break;
 173
 174                 if (*buf.buf == '*') {
 175                         capname = buf.buf + 1;
 176                         mandatory = 1;
 177                 } else
 178                         capname = buf.buf;
 179
 180                 if (debug)
 181                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 182                 if (!strcmp(capname, "fetch"))
 183                         data->fetch = 1;
 184                 else if (!strcmp(capname, "option"))
 185                         data->option = 1;
 186                 else if (!strcmp(capname, "push"))
 187                         data->push = 1;
 188                 else if (!strcmp(capname, "import"))
 189                         data->import = 1;
 190                 else if (!strcmp(capname, "bidi-import"))
 191                         data->bidi_import = 1;
 192                 else if (!strcmp(capname, "export"))
 193                         data->export = 1;
 194                 else if (!strcmp(capname, "check-connectivity"))
 195                         data->check_connectivity = 1;
 196                 else if (skip_prefix(capname, "refspec ", &arg)) {
 197                         refspec_append(&data->rs, arg);
 198                 } else if (!strcmp(capname, "connect")) {
 199                         data->connect = 1;
 200                 } else if (!strcmp(capname, "stateless-connect")) {
 201                         data->stateless_connect = 1;
 202                 } else if (!strcmp(capname, "signed-tags")) {
 203                         data->signed_tags = 1;
 204                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 205                         data->export_marks = xstrdup(arg);
 206                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 207                         data->import_marks = xstrdup(arg);
 208                 } else if (starts_with(capname, "no-private-update")) {
 209                         data->no_private_update = 1;
 210                 } else if (mandatory) {
 211                         die(_("unknown mandatory capability %s; this remote "
 212                               "helper probably needs newer version of Git"),
 213                             capname);
 214                 }
 215         }
 216         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
 217                 warning(_("this remote helper should implement refspec capability"));
 218         }
 219         strbuf_release(&buf);
 220         if (debug)
 221                 fprintf(stderr, "Debug: Capabilities complete.\n");
 222         standard_options(transport);
 223         return data->helper;
 224 }
 225
 226 static int disconnect_helper(struct transport *transport)
 227 {
 228         struct helper_data *data = transport->data;
 229         int res = 0;
 230
 231         if (data->helper) {
 232                 if (debug)
 233                         fprintf(stderr, "Debug: Disconnecting.\n");
 234                 if (!data->no_disconnect_req) {
 235                         /*
 236                          * Ignore write errors; there's nothing we can do,
 237                          * since we're about to close the pipe anyway. And the
 238                          * most likely error is EPIPE due to the helper dying
 239                          * to report an error itself.
 240                          */
 241                         sigchain_push(SIGPIPE, SIG_IGN);
 242                         xwrite(data->helper->in, "\n", 1);
 243                         sigchain_pop(SIGPIPE);
 244                 }
 245                 close(data->helper->in);
 246                 close(data->helper->out);
 247                 fclose(data->out);
 248                 res = finish_command(data->helper);
 249                 FREE_AND_NULL(data->helper);
 250         }
 251         return res;
 252 }
 253
 254 static const char *unsupported_options[] = {
 255         TRANS_OPT_UPLOADPACK,
 256         TRANS_OPT_RECEIVEPACK,
 257         TRANS_OPT_THIN,
 258         TRANS_OPT_KEEP
 259         };
 260
 261 static const char *boolean_options[] = {
 262         TRANS_OPT_THIN,
 263         TRANS_OPT_KEEP,
 264         TRANS_OPT_FOLLOWTAGS,
 265         TRANS_OPT_DEEPEN_RELATIVE
 266         };
 267
 268 static int strbuf_set_helper_option(struct helper_data *data,
 269                                     struct strbuf *buf)
 270 {
 271         int ret;
 272
 273         sendline(data, buf);
 274         if (recvline(data, buf))
 275                 exit(128);
 276
 277         if (!strcmp(buf->buf, "ok"))
 278                 ret = 0;
 279         else if (starts_with(buf->buf, "error"))
 280                 ret = -1;
 281         else if (!strcmp(buf->buf, "unsupported"))
 282                 ret = 1;
 283         else {
 284                 warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
 285                 ret = 1;
 286         }
 287         return ret;
 288 }
 289
 290 static int string_list_set_helper_option(struct helper_data *data,
 291                                          const char *name,
 292                                          struct string_list *list)
 293 {
 294         struct strbuf buf = STRBUF_INIT;
 295         int i, ret = 0;
 296
 297         for (i = 0; i < list->nr; i++) {
 298                 strbuf_addf(&buf, "option %s ", name);
 299                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 300                 strbuf_addch(&buf, '\n');
 301
 302                 if ((ret = strbuf_set_helper_option(data, &buf)))
 303                         break;
 304                 strbuf_reset(&buf);
 305         }
 306         strbuf_release(&buf);
 307         return ret;
 308 }
 309
 310 static int set_helper_option(struct transport *transport,
 311                           const char *name, const char *value)
 312 {
 313         struct helper_data *data = transport->data;
 314         struct strbuf buf = STRBUF_INIT;
 315         int i, ret, is_bool = 0;
 316
 317         get_helper(transport);
 318
 319         if (!data->option)
 320                 return 1;
 321
 322         if (!strcmp(name, "deepen-not"))
 323                 return string_list_set_helper_option(data, name,
 324                                                      (struct string_list *)value);
 325
 326         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 327                 if (!strcmp(name, unsupported_options[i]))
 328                         return 1;
 329         }
 330
 331         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 332                 if (!strcmp(name, boolean_options[i])) {
 333                         is_bool = 1;
 334                         break;
 335                 }
 336         }
 337
 338         strbuf_addf(&buf, "option %s ", name);
 339         if (is_bool)
 340                 strbuf_addstr(&buf, value ? "true" : "false");
 341         else
 342                 quote_c_style(value, &buf, NULL, 0);
 343         strbuf_addch(&buf, '\n');
 344
 345         ret = strbuf_set_helper_option(data, &buf);
 346         strbuf_release(&buf);
 347         return ret;
 348 }
 349
 350 static void standard_options(struct transport *t)
 351 {
 352         char buf[16];
 353         int v = t->verbose;
 354
 355         set_helper_option(t, "progress", t->progress ? "true" : "false");
 356
 357         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 358         set_helper_option(t, "verbosity", buf);
 359
 360         switch (t->family) {
 361         case TRANSPORT_FAMILY_ALL:
 362                 /*
 363                  * this is already the default,
 364                  * do not break old remote helpers by setting "all" here
 365                  */
 366                 break;
 367         case TRANSPORT_FAMILY_IPV4:
 368                 set_helper_option(t, "family", "ipv4");
 369                 break;
 370         case TRANSPORT_FAMILY_IPV6:
 371                 set_helper_option(t, "family", "ipv6");
 372                 break;
 373         }
 374 }
 375
 376 static int release_helper(struct transport *transport)
 377 {
 378         int res = 0;
 379         struct helper_data *data = transport->data;
 380         refspec_clear(&data->rs);
 381         res = disconnect_helper(transport);
 382         free(transport->data);
 383         return res;
 384 }
 385
 386 static int fetch_with_fetch(struct transport *transport,
 387                             int nr_heads, struct ref **to_fetch)
 388 {
 389         struct helper_data *data = transport->data;
 390         int i;
 391         struct strbuf buf = STRBUF_INIT;
 392
 393         for (i = 0; i < nr_heads; i++) {
 394                 const struct ref *posn = to_fetch[i];
 395                 if (posn->status & REF_STATUS_UPTODATE)
 396                         continue;
 397
 398                 strbuf_addf(&buf, "fetch %s %s\n",
 399                             oid_to_hex(&posn->old_oid),
 400                             posn->symref ? posn->symref : posn->name);
 401         }
 402
 403         strbuf_addch(&buf, '\n');
 404         sendline(data, &buf);
 405
 406         while (1) {
 407                 if (recvline(data, &buf))
 408                         exit(128);
 409
 410                 if (starts_with(buf.buf, "lock ")) {
 411                         const char *name = buf.buf + 5;
 412                         if (transport->pack_lockfile)
 413                                 warning(_("%s also locked %s"), data->name, name);
 414                         else
 415                                 transport->pack_lockfile = xstrdup(name);
 416                 }
 417                 else if (data->check_connectivity &&
 418                          data->transport_options.check_self_contained_and_connected &&
 419                          !strcmp(buf.buf, "connectivity-ok"))
 420                         data->transport_options.self_contained_and_connected = 1;
 421                 else if (!buf.len)
 422                         break;
 423                 else
 424                         warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
 425         }
 426         strbuf_release(&buf);
 427         return 0;
 428 }
 429
 430 static int get_importer(struct transport *transport, struct child_process *fastimport)
 431 {
 432         struct child_process *helper = get_helper(transport);
 433         struct helper_data *data = transport->data;
 434         int cat_blob_fd, code;
 435         child_process_init(fastimport);
 436         fastimport->in = xdup(helper->out);
 437         argv_array_push(&fastimport->args, "fast-import");
 438         argv_array_push(&fastimport->args, "--allow-unsafe-features");
 439         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 440
 441         if (data->bidi_import) {
 442                 cat_blob_fd = xdup(helper->in);
 443                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 444         }
 445         fastimport->git_cmd = 1;
 446
 447         code = start_command(fastimport);
 448         return code;
 449 }
 450
 451 static int get_exporter(struct transport *transport,
 452                         struct child_process *fastexport,
 453                         struct string_list *revlist_args)
 454 {
 455         struct helper_data *data = transport->data;
 456         struct child_process *helper = get_helper(transport);
 457         int i;
 458
 459         child_process_init(fastexport);
 460
 461         /* we need to duplicate helper->in because we want to use it after
 462          * fastexport is done with it. */
 463         fastexport->out = dup(helper->in);
 464         argv_array_push(&fastexport->args, "fast-export");
 465         argv_array_push(&fastexport->args, "--use-done-feature");
 466         argv_array_push(&fastexport->args, data->signed_tags ?
 467                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 468         if (data->export_marks)
 469                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 470         if (data->import_marks)
 471                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 472
 473         for (i = 0; i < revlist_args->nr; i++)
 474                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 475
 476         fastexport->git_cmd = 1;
 477         return start_command(fastexport);
 478 }
 479
 480 static int fetch_with_import(struct transport *transport,
 481                              int nr_heads, struct ref **to_fetch)
 482 {
 483         struct child_process fastimport;
 484         struct helper_data *data = transport->data;
 485         int i;
 486         struct ref *posn;
 487         struct strbuf buf = STRBUF_INIT;
 488
 489         get_helper(transport);
 490
 491         if (get_importer(transport, &fastimport))
 492                 die(_("couldn't run fast-import"));
 493
 494         for (i = 0; i < nr_heads; i++) {
 495                 posn = to_fetch[i];
 496                 if (posn->status & REF_STATUS_UPTODATE)
 497                         continue;
 498
 499                 strbuf_addf(&buf, "import %s\n",
 500                             posn->symref ? posn->symref : posn->name);
 501                 sendline(data, &buf);
 502                 strbuf_reset(&buf);
 503         }
 504
 505         write_constant(data->helper->in, "\n");
 506         /*
 507          * remote-helpers that advertise the bidi-import capability are required to
 508          * buffer the complete batch of import commands until this newline before
 509          * sending data to fast-import.
 510          * These helpers read back data from fast-import on their stdin, which could
 511          * be mixed with import commands, otherwise.
 512          */
 513
 514         if (finish_command(&fastimport))
 515                 die(_("error while running fast-import"));
 516
 517         /*
 518          * The fast-import stream of a remote helper that advertises
 519          * the "refspec" capability writes to the refs named after the
 520          * right hand side of the first refspec matching each ref we
 521          * were fetching.
 522          *
 523          * (If no "refspec" capability was specified, for historical
 524          * reasons we default to the equivalent of *:*.)
 525          *
 526          * Store the result in to_fetch[i].old_sha1.  Callers such
 527          * as "git fetch" can use the value to write feedback to the
 528          * terminal, populate FETCH_HEAD, and determine what new value
 529          * should be written to peer_ref if the update is a
 530          * fast-forward or this is a forced update.
 531          */
 532         for (i = 0; i < nr_heads; i++) {
 533                 char *private, *name;
 534                 posn = to_fetch[i];
 535                 if (posn->status & REF_STATUS_UPTODATE)
 536                         continue;
 537                 name = posn->symref ? posn->symref : posn->name;
 538                 if (data->rs.nr)
 539                         private = apply_refspecs(&data->rs, name);
 540                 else
 541                         private = xstrdup(name);
 542                 if (private) {
 543                         if (read_ref(private, &posn->old_oid) < 0)
 544                                 die(_("could not read ref %s"), private);
 545                         free(private);
 546                 }
 547         }
 548         strbuf_release(&buf);
 549         return 0;
 550 }
 551
 552 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 553 {
 554         struct helper_data *data = transport->data;
 555         int ret = 0;
 556         int duped;
 557         FILE *input;
 558         struct child_process *helper;
 559
 560         helper = get_helper(transport);
 561
 562         /*
 563          * Yes, dup the pipe another time, as we need unbuffered version
 564          * of input pipe as FILE*. fclose() closes the underlying fd and
 565          * stream buffering only can be changed before first I/O operation
 566          * on it.
 567          */
 568         duped = dup(helper->out);
 569         if (duped < 0)
 570                 die_errno(_("can't dup helper output fd"));
 571         input = xfdopen(duped, "r");
 572         setvbuf(input, NULL, _IONBF, 0);
 573
 574         sendline(data, cmdbuf);
 575         if (recvline_fh(input, cmdbuf))
 576                 exit(128);
 577
 578         if (!strcmp(cmdbuf->buf, "")) {
 579                 data->no_disconnect_req = 1;
 580                 if (debug)
 581                         fprintf(stderr, "Debug: Smart transport connection "
 582                                 "ready.\n");
 583                 ret = 1;
 584         } else if (!strcmp(cmdbuf->buf, "fallback")) {
 585                 if (debug)
 586                         fprintf(stderr, "Debug: Falling back to dumb "
 587                                 "transport.\n");
 588         } else {
 589                 die(_("unknown response to connect: %s"),
 590                     cmdbuf->buf);
 591         }
 592
 593         fclose(input);
 594         return ret;
 595 }
 596
 597 static int process_connect_service(struct transport *transport,
 598                                    const char *name, const char *exec)
 599 {
 600         struct helper_data *data = transport->data;
 601         struct strbuf cmdbuf = STRBUF_INIT;
 602         int ret = 0;
 603
 604         /*
 605          * Handle --upload-pack and friends. This is fire and forget...
 606          * just warn if it fails.
 607          */
 608         if (strcmp(name, exec)) {
 609                 int r = set_helper_option(transport, "servpath", exec);
 610                 if (r > 0)
 611                         warning(_("setting remote service path not supported by protocol"));
 612                 else if (r < 0)
 613                         warning(_("invalid remote service path"));
 614         }
 615
 616         if (data->connect) {
 617                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 618                 ret = run_connect(transport, &cmdbuf);
 619         } else if (data->stateless_connect &&
 620                    (get_protocol_version_config() == protocol_v2) &&
 621                    !strcmp("git-upload-pack", name)) {
 622                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 623                 ret = run_connect(transport, &cmdbuf);
 624                 if (ret)
 625                         transport->stateless_rpc = 1;
 626         }
 627
 628         strbuf_release(&cmdbuf);
 629         return ret;
 630 }
 631
 632 static int process_connect(struct transport *transport,
 633                                      int for_push)
 634 {
 635         struct helper_data *data = transport->data;
 636         const char *name;
 637         const char *exec;
 638
 639         name = for_push ? "git-receive-pack" : "git-upload-pack";
 640         if (for_push)
 641                 exec = data->transport_options.receivepack;
 642         else
 643                 exec = data->transport_options.uploadpack;
 644
 645         return process_connect_service(transport, name, exec);
 646 }
 647
 648 static int connect_helper(struct transport *transport, const char *name,
 649                    const char *exec, int fd[2])
 650 {
 651         struct helper_data *data = transport->data;
 652
 653         /* Get_helper so connect is inited. */
 654         get_helper(transport);
 655         if (!data->connect)
 656                 die(_("operation not supported by protocol"));
 657
 658         if (!process_connect_service(transport, name, exec))
 659                 die(_("can't connect to subservice %s"), name);
 660
 661         fd[0] = data->helper->out;
 662         fd[1] = data->helper->in;
 663         return 0;
 664 }
 665
 666 static struct ref *get_refs_list_using_list(struct transport *transport,
 667                                             int for_push);
 668
 669 static int fetch(struct transport *transport,
 670                  int nr_heads, struct ref **to_fetch)
 671 {
 672         struct helper_data *data = transport->data;
 673         int i, count;
 674
 675         get_helper(transport);
 676
 677         if (process_connect(transport, 0)) {
 678                 do_take_over(transport);
 679                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
 680         }
 681
 682         if (!data->get_refs_list_called)
 683                 get_refs_list_using_list(transport, 0);
 684
 685         count = 0;
 686         for (i = 0; i < nr_heads; i++)
 687                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 688                         count++;
 689
 690         if (!count)
 691                 return 0;
 692
 693         if (data->check_connectivity &&
 694             data->transport_options.check_self_contained_and_connected)
 695                 set_helper_option(transport, "check-connectivity", "true");
 696
 697         if (transport->cloning)
 698                 set_helper_option(transport, "cloning", "true");
 699
 700         if (data->transport_options.update_shallow)
 701                 set_helper_option(transport, "update-shallow", "true");
 702
 703         if (data->transport_options.filter_options.choice) {
 704                 const char *spec = expand_list_objects_filter_spec(
 705                         &data->transport_options.filter_options);
 706                 set_helper_option(transport, "filter", spec);
 707         }
 708
 709         if (data->transport_options.negotiation_tips)
 710                 warning("Ignoring --negotiation-tip because the protocol does not support it.");
 711
 712         if (data->fetch)
 713                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 714
 715         if (data->import)
 716                 return fetch_with_import(transport, nr_heads, to_fetch);
 717
 718         return -1;
 719 }
 720
 721 static int push_update_ref_status(struct strbuf *buf,
 722                                    struct ref **ref,
 723                                    struct ref *remote_refs)
 724 {
 725         char *refname, *msg;
 726         int status, forced = 0;
 727
 728         if (starts_with(buf->buf, "ok ")) {
 729                 status = REF_STATUS_OK;
 730                 refname = buf->buf + 3;
 731         } else if (starts_with(buf->buf, "error ")) {
 732                 status = REF_STATUS_REMOTE_REJECT;
 733                 refname = buf->buf + 6;
 734         } else
 735                 die(_("expected ok/error, helper said '%s'"), buf->buf);
 736
 737         msg = strchr(refname, ' ');
 738         if (msg) {
 739                 struct strbuf msg_buf = STRBUF_INIT;
 740                 const char *end;
 741
 742                 *msg++ = '\0';
 743                 if (!unquote_c_style(&msg_buf, msg, &end))
 744                         msg = strbuf_detach(&msg_buf, NULL);
 745                 else
 746                         msg = xstrdup(msg);
 747                 strbuf_release(&msg_buf);
 748
 749                 if (!strcmp(msg, "no match")) {
 750                         status = REF_STATUS_NONE;
 751                         FREE_AND_NULL(msg);
 752                 }
 753                 else if (!strcmp(msg, "up to date")) {
 754                         status = REF_STATUS_UPTODATE;
 755                         FREE_AND_NULL(msg);
 756                 }
 757                 else if (!strcmp(msg, "non-fast forward")) {
 758                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 759                         FREE_AND_NULL(msg);
 760                 }
 761                 else if (!strcmp(msg, "already exists")) {
 762                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 763                         FREE_AND_NULL(msg);
 764                 }
 765                 else if (!strcmp(msg, "fetch first")) {
 766                         status = REF_STATUS_REJECT_FETCH_FIRST;
 767                         FREE_AND_NULL(msg);
 768                 }
 769                 else if (!strcmp(msg, "needs force")) {
 770                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 771                         FREE_AND_NULL(msg);
 772                 }
 773                 else if (!strcmp(msg, "stale info")) {
 774                         status = REF_STATUS_REJECT_STALE;
 775                         FREE_AND_NULL(msg);
 776                 }
 777                 else if (!strcmp(msg, "forced update")) {
 778                         forced = 1;
 779                         FREE_AND_NULL(msg);
 780                 }
 781         }
 782
 783         if (*ref)
 784                 *ref = find_ref_by_name(*ref, refname);
 785         if (!*ref)
 786                 *ref = find_ref_by_name(remote_refs, refname);
 787         if (!*ref) {
 788                 warning(_("helper reported unexpected status of %s"), refname);
 789                 return 1;
 790         }
 791
 792         if ((*ref)->status != REF_STATUS_NONE) {
 793                 /*
 794                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 795                  * status reported by the remote helper if the latter is 'no match'.
 796                  */
 797                 if (status == REF_STATUS_NONE)
 798                         return 1;
 799         }
 800
 801         (*ref)->status = status;
 802         (*ref)->forced_update |= forced;
 803         (*ref)->remote_status = msg;
 804         return !(status == REF_STATUS_OK);
 805 }
 806
 807 static int push_update_refs_status(struct helper_data *data,
 808                                     struct ref *remote_refs,
 809                                     int flags)
 810 {
 811         struct strbuf buf = STRBUF_INIT;
 812         struct ref *ref = remote_refs;
 813         int ret = 0;
 814
 815         for (;;) {
 816                 char *private;
 817
 818                 if (recvline(data, &buf)) {
 819                         ret = 1;
 820                         break;
 821                 }
 822
 823                 if (!buf.len)
 824                         break;
 825
 826                 if (push_update_ref_status(&buf, &ref, remote_refs))
 827                         continue;
 828
 829                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
 830                         continue;
 831
 832                 /* propagate back the update to the remote namespace */
 833                 private = apply_refspecs(&data->rs, ref->name);
 834                 if (!private)
 835                         continue;
 836                 update_ref("update by helper", private, &ref->new_oid, NULL,
 837                            0, 0);
 838                 free(private);
 839         }
 840         strbuf_release(&buf);
 841         return ret;
 842 }
 843
 844 static void set_common_push_options(struct transport *transport,
 845                                    const char *name, int flags)
 846 {
 847         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 848                 if (set_helper_option(transport, "dry-run", "true") != 0)
 849                         die(_("helper %s does not support dry-run"), name);
 850         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 851                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 852                         die(_("helper %s does not support --signed"), name);
 853         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 854                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 855                         die(_("helper %s does not support --signed=if-asked"), name);
 856         }
 857
 858         if (flags & TRANSPORT_PUSH_ATOMIC)
 859                 if (set_helper_option(transport, TRANS_OPT_ATOMIC, "true") != 0)
 860                         die(_("helper %s does not support --atomic"), name);
 861
 862         if (flags & TRANSPORT_PUSH_OPTIONS) {
 863                 struct string_list_item *item;
 864                 for_each_string_list_item(item, transport->push_options)
 865                         if (set_helper_option(transport, "push-option", item->string) != 0)
 866                                 die(_("helper %s does not support 'push-option'"), name);
 867         }
 868 }
 869
 870 static int push_refs_with_push(struct transport *transport,
 871                                struct ref *remote_refs, int flags)
 872 {
 873         int force_all = flags & TRANSPORT_PUSH_FORCE;
 874         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 875         int atomic = flags & TRANSPORT_PUSH_ATOMIC;
 876         struct helper_data *data = transport->data;
 877         struct strbuf buf = STRBUF_INIT;
 878         struct ref *ref;
 879         struct string_list cas_options = STRING_LIST_INIT_DUP;
 880         struct string_list_item *cas_option;
 881
 882         get_helper(transport);
 883         if (!data->push)
 884                 return 1;
 885
 886         for (ref = remote_refs; ref; ref = ref->next) {
 887                 if (!ref->peer_ref && !mirror)
 888                         continue;
 889
 890                 /* Check for statuses set by set_ref_status_for_push() */
 891                 switch (ref->status) {
 892                 case REF_STATUS_REJECT_NONFASTFORWARD:
 893                 case REF_STATUS_REJECT_STALE:
 894                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 895                         if (atomic) {
 896                                 string_list_clear(&cas_options, 0);
 897                                 return 0;
 898                         } else
 899                                 continue;
 900                 case REF_STATUS_UPTODATE:
 901                         continue;
 902                 default:
 903                         ; /* do nothing */
 904                 }
 905
 906                 if (force_all)
 907                         ref->force = 1;
 908
 909                 strbuf_addstr(&buf, "push ");
 910                 if (!ref->deletion) {
 911                         if (ref->force)
 912                                 strbuf_addch(&buf, '+');
 913                         if (ref->peer_ref)
 914                                 strbuf_addstr(&buf, ref->peer_ref->name);
 915                         else
 916                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 917                 }
 918                 strbuf_addch(&buf, ':');
 919                 strbuf_addstr(&buf, ref->name);
 920                 strbuf_addch(&buf, '\n');
 921
 922                 /*
 923                  * The "--force-with-lease" options without explicit
 924                  * values to expect have already been expanded into
 925                  * the ref->old_oid_expect[] field; we can ignore
 926                  * transport->smart_options->cas altogether and instead
 927                  * can enumerate them from the refs.
 928                  */
 929                 if (ref->expect_old_sha1) {
 930                         struct strbuf cas = STRBUF_INIT;
 931                         strbuf_addf(&cas, "%s:%s",
 932                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 933                         string_list_append_nodup(&cas_options,
 934                                                  strbuf_detach(&cas, NULL));
 935                 }
 936         }
 937         if (buf.len == 0) {
 938                 string_list_clear(&cas_options, 0);
 939                 return 0;
 940         }
 941
 942         for_each_string_list_item(cas_option, &cas_options)
 943                 set_helper_option(transport, "cas", cas_option->string);
 944         set_common_push_options(transport, data->name, flags);
 945
 946         strbuf_addch(&buf, '\n');
 947         sendline(data, &buf);
 948         strbuf_release(&buf);
 949         string_list_clear(&cas_options, 0);
 950
 951         return push_update_refs_status(data, remote_refs, flags);
 952 }
 953
 954 static int push_refs_with_export(struct transport *transport,
 955                 struct ref *remote_refs, int flags)
 956 {
 957         struct ref *ref;
 958         struct child_process *helper, exporter;
 959         struct helper_data *data = transport->data;
 960         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 961         struct strbuf buf = STRBUF_INIT;
 962
 963         if (!data->rs.nr)
 964                 die(_("remote-helper doesn't support push; refspec needed"));
 965
 966         set_common_push_options(transport, data->name, flags);
 967         if (flags & TRANSPORT_PUSH_FORCE) {
 968                 if (set_helper_option(transport, "force", "true") != 0)
 969                         warning(_("helper %s does not support 'force'"), data->name);
 970         }
 971
 972         helper = get_helper(transport);
 973
 974         write_constant(helper->in, "export\n");
 975
 976         for (ref = remote_refs; ref; ref = ref->next) {
 977                 char *private;
 978                 struct object_id oid;
 979
 980                 private = apply_refspecs(&data->rs, ref->name);
 981                 if (private && !get_oid(private, &oid)) {
 982                         strbuf_addf(&buf, "^%s", private);
 983                         string_list_append_nodup(&revlist_args,
 984                                                  strbuf_detach(&buf, NULL));
 985                         oidcpy(&ref->old_oid, &oid);
 986                 }
 987                 free(private);
 988
 989                 if (ref->peer_ref) {
 990                         if (strcmp(ref->name, ref->peer_ref->name)) {
 991                                 if (!ref->deletion) {
 992                                         const char *name;
 993                                         int flag;
 994
 995                                         /* Follow symbolic refs (mainly for HEAD). */
 996                                         name = resolve_ref_unsafe(ref->peer_ref->name,
 997                                                                   RESOLVE_REF_READING,
 998                                                                   &oid, &flag);
 999                                         if (!name || !(flag & REF_ISSYMREF))
1000                                                 name = ref->peer_ref->name;
1001
1002                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
1003                                 } else
1004                                         strbuf_addf(&buf, ":%s", ref->name);
1005
1006                                 string_list_append(&revlist_args, "--refspec");
1007                                 string_list_append(&revlist_args, buf.buf);
1008                                 strbuf_release(&buf);
1009                         }
1010                         if (!ref->deletion)
1011                                 string_list_append(&revlist_args, ref->peer_ref->name);
1012                 }
1013         }
1014
1015         if (get_exporter(transport, &exporter, &revlist_args))
1016                 die(_("couldn't run fast-export"));
1017
1018         string_list_clear(&revlist_args, 1);
1019
1020         if (finish_command(&exporter))
1021                 die(_("error while running fast-export"));
1022         if (push_update_refs_status(data, remote_refs, flags))
1023                 return 1;
1024
1025         if (data->export_marks) {
1026                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
1027                 rename(buf.buf, data->export_marks);
1028                 strbuf_release(&buf);
1029         }
1030
1031         return 0;
1032 }
1033
1034 static int push_refs(struct transport *transport,
1035                 struct ref *remote_refs, int flags)
1036 {
1037         struct helper_data *data = transport->data;
1038
1039         if (process_connect(transport, 1)) {
1040                 do_take_over(transport);
1041                 return transport->vtable->push_refs(transport, remote_refs, flags);
1042         }
1043
1044         if (!remote_refs) {
1045                 fprintf(stderr,
1046                         _("No refs in common and none specified; doing nothing.\n"
1047                           "Perhaps you should specify a branch such as 'master'.\n"));
1048                 return 0;
1049         }
1050
1051         if (data->push)
1052                 return push_refs_with_push(transport, remote_refs, flags);
1053
1054         if (data->export)
1055                 return push_refs_with_export(transport, remote_refs, flags);
1056
1057         return -1;
1058 }
1059
1060
1061 static int has_attribute(const char *attrs, const char *attr)
1062 {
1063         int len;
1064         if (!attrs)
1065                 return 0;
1066
1067         len = strlen(attr);
1068         for (;;) {
1069                 const char *space = strchrnul(attrs, ' ');
1070                 if (len == space - attrs && !strncmp(attrs, attr, len))
1071                         return 1;
1072                 if (!*space)
1073                         return 0;
1074                 attrs = space + 1;
1075         }
1076 }
1077
1078 static struct ref *get_refs_list(struct transport *transport, int for_push,
1079                                  const struct argv_array *ref_prefixes)
1080 {
1081         get_helper(transport);
1082
1083         if (process_connect(transport, for_push)) {
1084                 do_take_over(transport);
1085                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1086         }
1087
1088         return get_refs_list_using_list(transport, for_push);
1089 }
1090
1091 static struct ref *get_refs_list_using_list(struct transport *transport,
1092                                             int for_push)
1093 {
1094         struct helper_data *data = transport->data;
1095         struct child_process *helper;
1096         struct ref *ret = NULL;
1097         struct ref **tail = &ret;
1098         struct ref *posn;
1099         struct strbuf buf = STRBUF_INIT;
1100
1101         data->get_refs_list_called = 1;
1102         helper = get_helper(transport);
1103
1104         if (data->push && for_push)
1105                 write_str_in_full(helper->in, "list for-push\n");
1106         else
1107                 write_str_in_full(helper->in, "list\n");
1108
1109         while (1) {
1110                 char *eov, *eon;
1111                 if (recvline(data, &buf))
1112                         exit(128);
1113
1114                 if (!*buf.buf)
1115                         break;
1116
1117                 eov = strchr(buf.buf, ' ');
1118                 if (!eov)
1119                         die(_("malformed response in ref list: %s"), buf.buf);
1120                 eon = strchr(eov + 1, ' ');
1121                 *eov = '\0';
1122                 if (eon)
1123                         *eon = '\0';
1124                 *tail = alloc_ref(eov + 1);
1125                 if (buf.buf[0] == '@')
1126                         (*tail)->symref = xstrdup(buf.buf + 1);
1127                 else if (buf.buf[0] != '?')
1128                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1129                 if (eon) {
1130                         if (has_attribute(eon + 1, "unchanged")) {
1131                                 (*tail)->status |= REF_STATUS_UPTODATE;
1132                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1133                                         die(_("could not read ref %s"),
1134                                             (*tail)->name);
1135                         }
1136                 }
1137                 tail = &((*tail)->next);
1138         }
1139         if (debug)
1140                 fprintf(stderr, "Debug: Read ref listing.\n");
1141         strbuf_release(&buf);
1142
1143         for (posn = ret; posn; posn = posn->next)
1144                 resolve_remote_symref(posn, ret);
1145
1146         return ret;
1147 }
1148
1149 static struct transport_vtable vtable = {
1150         set_helper_option,
1151         get_refs_list,
1152         fetch,
1153         push_refs,
1154         connect_helper,
1155         release_helper
1156 };
1157
1158 int transport_helper_init(struct transport *transport, const char *name)
1159 {
1160         struct helper_data *data = xcalloc(1, sizeof(*data));
1161         data->name = name;
1162
1163         transport_check_allowed(name);
1164
1165         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1166                 debug = 1;
1167
1168         transport->data = data;
1169         transport->vtable = &vtable;
1170         transport->smart_options = &(data->transport_options);
1171         return 0;
1172 }
1173
1174 /*
1175  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1176  * buffer less), so attempt reads and writes with up to that size.
1177  */
1178 #define BUFFERSIZE 65536
1179 /* This should be enough to hold debugging message. */
1180 #define PBUFFERSIZE 8192
1181
1182 /* Print bidirectional transfer loop debug message. */
1183 __attribute__((format (printf, 1, 2)))
1184 static void transfer_debug(const char *fmt, ...)
1185 {
1186         /*
1187          * NEEDSWORK: This function is sometimes used from multiple threads, and
1188          * we end up using debug_enabled racily. That "should not matter" since
1189          * we always write the same value, but it's still wrong. This function
1190          * is listed in .tsan-suppressions for the time being.
1191          */
1192
1193         va_list args;
1194         char msgbuf[PBUFFERSIZE];
1195         static int debug_enabled = -1;
1196
1197         if (debug_enabled < 0)
1198                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1199         if (!debug_enabled)
1200                 return;
1201
1202         va_start(args, fmt);
1203         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1204         va_end(args);
1205         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1206 }
1207
1208 /* Stream state: More data may be coming in this direction. */
1209 #define SSTATE_TRANSFERRING 0
1210 /*
1211  * Stream state: No more data coming in this direction, flushing rest of
1212  * data.
1213  */
1214 #define SSTATE_FLUSHING 1
1215 /* Stream state: Transfer in this direction finished. */
1216 #define SSTATE_FINISHED 2
1217
1218 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1219 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1220 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1221
1222 /* Unidirectional transfer. */
1223 struct unidirectional_transfer {
1224         /* Source */
1225         int src;
1226         /* Destination */
1227         int dest;
1228         /* Is source socket? */
1229         int src_is_sock;
1230         /* Is destination socket? */
1231         int dest_is_sock;
1232         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1233         int state;
1234         /* Buffer. */
1235         char buf[BUFFERSIZE];
1236         /* Buffer used. */
1237         size_t bufuse;
1238         /* Name of source. */
1239         const char *src_name;
1240         /* Name of destination. */
1241         const char *dest_name;
1242 };
1243
1244 /* Closes the target (for writing) if transfer has finished. */
1245 static void udt_close_if_finished(struct unidirectional_transfer *t)
1246 {
1247         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1248                 t->state = SSTATE_FINISHED;
1249                 if (t->dest_is_sock)
1250                         shutdown(t->dest, SHUT_WR);
1251                 else
1252                         close(t->dest);
1253                 transfer_debug("Closed %s.", t->dest_name);
1254         }
1255 }
1256
1257 /*
1258  * Tries to read data from source into buffer. If buffer is full,
1259  * no data is read. Returns 0 on success, -1 on error.
1260  */
1261 static int udt_do_read(struct unidirectional_transfer *t)
1262 {
1263         ssize_t bytes;
1264
1265         if (t->bufuse == BUFFERSIZE)
1266                 return 0;       /* No space for more. */
1267
1268         transfer_debug("%s is readable", t->src_name);
1269         bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1270         if (bytes < 0) {
1271                 error_errno(_("read(%s) failed"), t->src_name);
1272                 return -1;
1273         } else if (bytes == 0) {
1274                 transfer_debug("%s EOF (with %i bytes in buffer)",
1275                         t->src_name, (int)t->bufuse);
1276                 t->state = SSTATE_FLUSHING;
1277         } else if (bytes > 0) {
1278                 t->bufuse += bytes;
1279                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1280                         (int)bytes, t->src_name, (int)t->bufuse);
1281         }
1282         return 0;
1283 }
1284
1285 /* Tries to write data from buffer into destination. If buffer is empty,
1286  * no data is written. Returns 0 on success, -1 on error.
1287  */
1288 static int udt_do_write(struct unidirectional_transfer *t)
1289 {
1290         ssize_t bytes;
1291
1292         if (t->bufuse == 0)
1293                 return 0;       /* Nothing to write. */
1294
1295         transfer_debug("%s is writable", t->dest_name);
1296         bytes = xwrite(t->dest, t->buf, t->bufuse);
1297         if (bytes < 0) {
1298                 error_errno(_("write(%s) failed"), t->dest_name);
1299                 return -1;
1300         } else if (bytes > 0) {
1301                 t->bufuse -= bytes;
1302                 if (t->bufuse)
1303                         memmove(t->buf, t->buf + bytes, t->bufuse);
1304                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1305                         (int)bytes, t->dest_name, (int)t->bufuse);
1306         }
1307         return 0;
1308 }
1309
1310
1311 /* State of bidirectional transfer loop. */
1312 struct bidirectional_transfer_state {
1313         /* Direction from program to git. */
1314         struct unidirectional_transfer ptg;
1315         /* Direction from git to program. */
1316         struct unidirectional_transfer gtp;
1317 };
1318
1319 static void *udt_copy_task_routine(void *udt)
1320 {
1321         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1322         while (t->state != SSTATE_FINISHED) {
1323                 if (STATE_NEEDS_READING(t->state))
1324                         if (udt_do_read(t))
1325                                 return NULL;
1326                 if (STATE_NEEDS_WRITING(t->state))
1327                         if (udt_do_write(t))
1328                                 return NULL;
1329                 if (STATE_NEEDS_CLOSING(t->state))
1330                         udt_close_if_finished(t);
1331         }
1332         return udt;     /* Just some non-NULL value. */
1333 }
1334
1335 #ifndef NO_PTHREADS
1336
1337 /*
1338  * Join thread, with appropriate errors on failure. Name is name for the
1339  * thread (for error messages). Returns 0 on success, 1 on failure.
1340  */
1341 static int tloop_join(pthread_t thread, const char *name)
1342 {
1343         int err;
1344         void *tret;
1345         err = pthread_join(thread, &tret);
1346         if (!tret) {
1347                 error(_("%s thread failed"), name);
1348                 return 1;
1349         }
1350         if (err) {
1351                 error(_("%s thread failed to join: %s"), name, strerror(err));
1352                 return 1;
1353         }
1354         return 0;
1355 }
1356
1357 /*
1358  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1359  * -1 on failure.
1360  */
1361 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1362 {
1363         pthread_t gtp_thread;
1364         pthread_t ptg_thread;
1365         int err;
1366         int ret = 0;
1367         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1368                 &s->gtp);
1369         if (err)
1370                 die(_("can't start thread for copying data: %s"), strerror(err));
1371         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1372                 &s->ptg);
1373         if (err)
1374                 die(_("can't start thread for copying data: %s"), strerror(err));
1375
1376         ret |= tloop_join(gtp_thread, "Git to program copy");
1377         ret |= tloop_join(ptg_thread, "Program to git copy");
1378         return ret;
1379 }
1380 #else
1381
1382 /* Close the source and target (for writing) for transfer. */
1383 static void udt_kill_transfer(struct unidirectional_transfer *t)
1384 {
1385         t->state = SSTATE_FINISHED;
1386         /*
1387          * Socket read end left open isn't a disaster if nobody
1388          * attempts to read from it (mingw compat headers do not
1389          * have SHUT_RD)...
1390          *
1391          * We can't fully close the socket since otherwise gtp
1392          * task would first close the socket it sends data to
1393          * while closing the ptg file descriptors.
1394          */
1395         if (!t->src_is_sock)
1396                 close(t->src);
1397         if (t->dest_is_sock)
1398                 shutdown(t->dest, SHUT_WR);
1399         else
1400                 close(t->dest);
1401 }
1402
1403 /*
1404  * Join process, with appropriate errors on failure. Name is name for the
1405  * process (for error messages). Returns 0 on success, 1 on failure.
1406  */
1407 static int tloop_join(pid_t pid, const char *name)
1408 {
1409         int tret;
1410         if (waitpid(pid, &tret, 0) < 0) {
1411                 error_errno(_("%s process failed to wait"), name);
1412                 return 1;
1413         }
1414         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1415                 error(_("%s process failed"), name);
1416                 return 1;
1417         }
1418         return 0;
1419 }
1420
1421 /*
1422  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1423  * -1 on failure.
1424  */
1425 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1426 {
1427         pid_t pid1, pid2;
1428         int ret = 0;
1429
1430         /* Fork thread #1: git to program. */
1431         pid1 = fork();
1432         if (pid1 < 0)
1433                 die_errno(_("can't start thread for copying data"));
1434         else if (pid1 == 0) {
1435                 udt_kill_transfer(&s->ptg);
1436                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1437         }
1438
1439         /* Fork thread #2: program to git. */
1440         pid2 = fork();
1441         if (pid2 < 0)
1442                 die_errno(_("can't start thread for copying data"));
1443         else if (pid2 == 0) {
1444                 udt_kill_transfer(&s->gtp);
1445                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1446         }
1447
1448         /*
1449          * Close both streams in parent as to not interfere with
1450          * end of file detection and wait for both tasks to finish.
1451          */
1452         udt_kill_transfer(&s->gtp);
1453         udt_kill_transfer(&s->ptg);
1454         ret |= tloop_join(pid1, "Git to program copy");
1455         ret |= tloop_join(pid2, "Program to git copy");
1456         return ret;
1457 }
1458 #endif
1459
1460 /*
1461  * Copies data from stdin to output and from input to stdout simultaneously.
1462  * Additionally filtering through given filter. If filter is NULL, uses
1463  * identity filter.
1464  */
1465 int bidirectional_transfer_loop(int input, int output)
1466 {
1467         struct bidirectional_transfer_state state;
1468
1469         /* Fill the state fields. */
1470         state.ptg.src = input;
1471         state.ptg.dest = 1;
1472         state.ptg.src_is_sock = (input == output);
1473         state.ptg.dest_is_sock = 0;
1474         state.ptg.state = SSTATE_TRANSFERRING;
1475         state.ptg.bufuse = 0;
1476         state.ptg.src_name = "remote input";
1477         state.ptg.dest_name = "stdout";
1478
1479         state.gtp.src = 0;
1480         state.gtp.dest = output;
1481         state.gtp.src_is_sock = 0;
1482         state.gtp.dest_is_sock = (input == output);
1483         state.gtp.state = SSTATE_TRANSFERRING;
1484         state.gtp.bufuse = 0;
1485         state.gtp.src_name = "stdin";
1486         state.gtp.dest_name = "remote output";
1487
1488         return tloop_spawnwait_tasks(&state);
1489 }